THE SOILS OF IRELAND. 33 



very uninviting to the agriculturist,- for the most part peat-covered. The 

 soils, when worth describing (as in the southern parts of Carlow and on the 

 slopes of the granitic masses), are gray sandy loams, naturally very deficient 

 in Hme and phosphates, but they contain potash and some soda resulting 

 from the decomposition of the felspathic constituents of granite. Through- 

 out east Waterford and Wexford gray loams are common, resulting from the 

 decay of felsites ; like the soils formed from granite these contain supplies 

 of alkalis, but are deficient in lime. 



In Antrim and east Londonderry, basalt, the prevailing rock, yields red 

 pulverulent loams, contrasting strongly with the soils formed from granite, 

 in that they contain lime and phosphate-yielding ingredients, and in being 

 deficient in potash. Though the fertihsing constituents in these soils are 

 )delded up slowly, the soils are frequently extremely rich. 



Were the soils throughout Ireland such as have been formed from the 

 rocks immediately underlying them, an ordinary geological map would in- 

 dicate, with a fair degree of precision, the nature and contents of the former ; 

 but this is not found to be the case except in the circumstances mentioned 

 on a previous page. The supervention of glacial conditions in the country, 

 m the remote past, has resulted in transplacements to a greater or less 

 extent, of soil-forming materials, which obscure the relations between the 

 soils and the several rock formations. These circumstances, though in 

 some instances operating adversely, are found in a far greater degree to have 

 worked beneficially to the agricultural interest : there has been a mingling of 

 components drawn from various sources which is generally conducive to 

 fertility ; and in the distribution of drifts carried from the central plain, 

 hundreds of square miles have been covered with valuable limestone 

 detritus, thus imparting to hundreds of thousands of acres a degree of 

 fertility ^\•hich otherwise they would not possess. 



Regarding the beneficial effects of mingling of soil components there is 

 little question that the richness of alluvial and drift soils of the Golden Vein 

 is attributable to detrital contributions from the Silurian and Red Sandstone 

 rocks of the Keeper Hills, and from the felsites, basalts, etc., of the Limerick 

 basin, mingling with the materials derived from the rich limestone of the 

 countr}-. The rich soils of Meath, North Kildare, and Dublin consist chiefly 

 of limestone detritus interspersed with contributions from sandstones, 

 granites, and other potash-yielding rocks ; and the Lagan Valley, clothed 

 with drift, owes its well-known fertility to glacially formed mixtures of com- 

 ponents drawn from basalt, and red marl on the one side, and Silurian grits 

 and slate on the other, added to decomposed New Red Sandstone — the pre- 

 vailing rock of the valley. The soils of the barony of Forth and of other 

 parts of Wexford, owe their fertility to transported limestone detritus ; and 

 similarly the best barley soils of Cork, Carlow, Queen's County, Louth, etc. 

 are of drift origin. 



The distribution of drifts may be judged from the accompanying small 

 map, prepared with a view to showing the ground covered with those 

 deposits — not all limestone detritus, however. The materials and mixtures 

 are well-nigh infinite in variety ; to represent even a fair classification of 

 them and of soils formed from them, as well as directly from the solid rock, 

 where no drifted materials occur, would demand a large scale detailed map. 

 In the production of such a map for agricultural purposes, while noting in a 

 general way the local nature of the drifts, especially as regards sub-soils, 

 I think a double system of classification could be adopted, with appropriate 

 colouring and other map indications, in which, as regards texture, sands and 

 gravels, brick clays, and the intermediate varieties, sandy loams, loams, and 



D 



